The lunar program performs date conversion between the Gregorian Solar
Calendar (SC) and the Chinese Lunar Calendar (LC).

Given a date in either calendar, the program also outputs the corresponding
"shengxiao" (animal of the year) and "ganzhi" characters.

The date range currently covered is from about 1900 A.D. to 2049 A.D.

The standard time of the Lunar Calendar is Beijing (Hong Kong) Standard Time,
not GMT.  Be sure to adjust appropriately for other time zones and "Daylight
Saving Time".